#pragma once
#include <iostream>
#include <vector>
#include <semaphore.h>
#include "LockGuard.hpp"

const int defaultsize = 5;


template<class T>
class RingQueue
{
private:
    void P(sem_t &sem)
    {
        sem_wait(&sem);
    }
    void V(sem_t &sem)
    {
        sem_post(&sem);
    }

public:
    RingQueue(int size = defaultsize)
    :_ringqueue(size), _size(size), _p_step(0), _c_step(0)
    {
        sem_init(&_space_sem, 0, size);
        sem_init(&_data_sem, 0, 0);

        pthread_mutex_init(&_p_mutex, nullptr);
        pthread_mutex_init(&_c_mutex, nullptr);
    }

    void Push(const T &in)
    {
        //生产
        P(_space_sem);
        {
            LockGuard lockGuard(&_p_mutex);//维持生产者间互斥关系
            _ringqueue[_p_step] = in;
            _p_step++;
            _p_step %= _size;
        }
        V(_data_sem);
    }

    void Pop(T *out)
    {
        //消费
        //先申请信号量，在申请锁，
        P(_data_sem);
        {
            LockGuard lockGuard(&_c_mutex);//维持消费者间互斥关系
            *out = _ringqueue[_c_step];
            _c_step++;
            _c_step %= _size;
        }
        V(_space_sem);
    }

    ~RingQueue()
    {
        sem_destroy(&_space_sem);
        sem_destroy(&_data_sem);
        
        pthread_mutex_destroy(&_p_mutex);
        pthread_mutex_destroy(&_c_mutex);

    }


private:
     std::vector<T> _ringqueue;
     int _size;

     int _p_step;//生产者的位置
     int _c_step;//消费者的位置

     sem_t _space_sem;//生产者
     sem_t _data_sem;//消费者

     pthread_mutex_t _p_mutex;
     pthread_mutex_t _c_mutex;     
};

